The present invention generally relates to dropout compensation circuits for reproduced video signals in reproducing apparatuses, and more particularly to a dropout compensation circuit capable of effectively compensating for dropouts in a luminance signal within a color video signal reproduced from a recording medium in a reproducing apparatus.
Generally, when reproducing a recorded signal from a rotary recording medium by a reproducing stylus, dropouts are instantaneously introduced in the reproduced signal in a case where the reproducing stylus skips due to dust particles, scratches, and the like on the surface of the rotary recording medium. These signal dropouts are also generated when reproducing a recording medium such as a magnetic tape. Accordingly, as a conventional circuit for compensating for the dropouts, there was a circuit consisting of a detecting circuit for detecting the dropout, a delay circuit for delaying the reproduced composite color video signal, and a circuit for using the output of the delay circuit instead of the dropout part of the reproduced composite color video signal when the dropout is detected by the detecting circuit.
However, a delay circuit having a wide frequency band must be used in order to delay the whole reproduced composite color video signal. Hence, there was a disadvantage in that the conventional dropout compensation circuit could not be constructed at low cost. Further, there was a problem in that when a delay operation is performed with a wide frequency band, it is difficult to match the phase of the color signal.
On the other hand, a delay line having glass as the medium for delaying a signal by an interval of 1H (H indicates a horizontal scanning period), that is, a so-called 1H glass delay line, is low in cost. However, the operational frequency band of the above 1H glass delay line is narrow, and cannot be used independently for the above described conventional dropout compensation circuit.